It is known in a wide range of fields to affix a label having a barcode or the like printed thereon to the packages of articles to manage the delivery of the articles in logistics and production processes. For example, there is an article delivery management system in which, when articles are transported, the information on the labels affixed to the packages packing the articles are read by a handy terminal or the like equipped with a barcode reader at the collection and delivery center to identify the articles, whereby, based on the identification information, the distribution channel of each article is determined, transfer of the article is confirmed, and so on. In such a system, in addition to reading the information on the labels and sorting the articles in accordance with the respective destinations, it is necessary to measure the size of each package to determine the capacity and the number of transport vehicles for transportation.
As a means for measuring the size of the package using a captured image, there is a size measurement device which, provided that the package packing an article has the shape of a cube or a rectangular parallelepiped and the label size is known, captures an image of the package and the label affixed thereto at the same time and measures the package size using the length of the label in the captured image as a reference length (for example, see JP2004-219255A).
However, when the size of an object is measured based on the captured image data thereof, how to determine the feature points (vertices in the case of a package) serving as a reference for size measurement of the object is significant. In a case where the feature points are extracted only by image processing for performing edge detection, etc., the processing is performed for the entire image data, and therefore, not only the processing load is large but also the object that the user desires to measure may not be extracted efficiently.
In a case where the user designates the feature points, it may be conceived to display the captured image data on a display device so that the user can designate the feature points by use of an input device. However, due to the hardware limitations related to the display device and the input device, it is difficult for the user to accurately indicate the coordinates serving as feature points.
Further, JP2004-219255A discloses that the user may designate vertices of a package by means of laser light. However, the vertices of a package and the laser light are ideally points, and it is not easy for the user to accurately irradiate laser light onto the vertices of a cardboard box at the site, for example.
A purpose of the present invention is to provide a size measurement device and a size measurement method capable of measuring the external size of a package having the shape of a cube or a rectangular parallelepiped with a high accuracy based on the designation performed easily by the user.